why would a CAD tools maker buy a web 2.0 company?
Because DS is not just CAD. They want to brand themselves as a 3D platform, not a simple engineering product. This opens doors to be a 3D platform for designers, architects (see LiveBuilding), consumers, etc.
Techno-Military organization purchasing a web congregator and watching user reading habits? Hmm ..
They have a genuine big business in CAD systems, which they sell more easily than Rafales...